Liquid fuel burner

ABSTRACT

A liquid fuel burner in which a hollow fuel gasifying member and a fuel diffusing member are mounted on a rotary shaft within the burner body for coaxial rotation and air under pressure is directed toward these members for atomizing liquid fuel. A narrow atomized fuel blowing gap is defined between the open end of the gasifying member and a central open space of a gas chamber so that the mixture of atomized fuel and air can be first ignited to heat the gasifying member to a high temperature for promoting later gasification of liquid fuel for continuous combustion.

llnited States Patent [1 1 Miyahara [111 3,81LM8 May 21, 1974 LIQUID FUEL BURNER [75] Inventor: Kingo Miyahara, Tokyo, Japan [73] Assignee: Kabushiki Kaisha Dowa, Tokyo,

Japan 22 Filed: Mar. 29, 1973 21 Appl. No.: 346,127

[ 30] Foreign Application Priority Data [58] Field of Search 431/168, 169; 239/2141], 239/2l4.l5, 214.17, 214.21, 214.25

Primary Examiner-Carroll B. Dority, Jr. Attorney, Agent, or Firm-Hill, Gross, Simpson, Van Santen, Steadman, Chiara & Simpson 57 ABSTRACT A liquid fuel burner in which a hollow fuel gasifying member and a fuel diffusing member are mounted on a rotary shaft within the burner body for coaxial rotation and air under pressure is directed toward these members for atomizing liquid fuel. A narrow atomized fuel blowing gap is defined between the open end of the gasifying member and a central open space of a gas chamber so that the mixture of atomized fuel and air can be first ignited to heat the gasifying member to a high temperature for promoting later gasification of l 56] References Cited liquid fuel for continuous combustion.

UNITED STATES PATENTS 4 Claims, 8 Drawing Figures 1 3,175,600 3/1965 Powell 431/168 3 l l4 l5 g g l2 4 I l l 7 .LI-LLLZLLM/ 77 1'1! III/77% H PATENTED 1m 2 1 1914 SHEEI 2 0F 3 FIG. 3

FIG. 4

LIQUID FUEL BURNER This invention relates to a liquid fuel burner for burning liquid fuel in gasified form.

In conventional liquid fuel burners of the kind in which liquid fuel is gasified and the gasified fuel is injected into a combustion chamber from a multiplicity of gasified fuel injectionopenings for the purpose of combustion, gasification of liquid fuel has been attained by the process including preheating the liquid fuel by preheating means such as an electric heater within a gasifying member or by the process including removing an injection plate fitted to thegasifying member, causing combustion of the liquid fuel within the gasifying member for preheating the gasifying member, fitting the injection plate to the gasifying member again and gasifying the liquid fuel by the heat of the preheated gasifying member.

However, while the former means utilizing the electric heating for preheating the liquid fuel has been advantageous in that the gasification and combustion can be automatically carried out, it has been defective in that a considerably long period of time is required for preheating, heater disconnection trouble occurs frequently and the burner is quite expensive. Further, the latter means has been defective in that inconvenience is encountered in the procedure for initiating the combustion and the combustion cannot be satisfactorily initiated unless the user is skilled considerably in handling of the burner although it has the advantage of simple construction.

It is therefore an object of the present invention to provide a novel and improved liquid fuel burner in which the initial state of combustion of liquid fuel in liquid form can be automatically shifted to the state of combustion in gasified form without the provision of any special means for preheating the liquid fuel.

Another object of the present invention is to provide a liquidfuel burner in which means are provided for causing diffusion of supplied liquid fuel along the inner surface of a rotating fuel gasifying member and directing a stream of air under pressure toward the inner surface of the gasifying member for promoting the atomization and gasification of the liquid fuel.

Still another object of the present invention is to provide a liquid fuel burner in which liquid fuel is first atomized and scattered by suitable means for ignition and the flame of the ignited fuel is utilized for heating the rotating fuel gasifying member to a high temperature.

Yet another object of the present invention is to provide a liquid fuel burner inwhich another stream of air under pressure is directed toward the liquid fuel portion diffusing along the inner surface of the fuel gasifying member or toward the already gasified fuel portion for further promoting the atomization of the fuel and mixing the gasified fuel and air thoroughly so that the gasification and combustion of the fuel can be continued over a long period of time.

A further object of the present invention is to provide a liquid fuel burner in which the liquid fuel and the gasified fuel are injected or blown from different portions so that the initial ignition of the liquid fuel can be automatically followed by the continuous combustion of the gasified fuel.

In. accordance to the present invention, there is provide a burner for burning liquid fuel in gasified form,

gas chamber for blowing gasified fuel into said combustion chamber, a rotary shaft extending coaxially into said main body and carrying a hollow fuel gasifying member at one end thereof, said fuel gasifying member having a fuel diffusing member provided on the inner surface thereof, said rotary shaft extending through said fuel diffusion member for rotation, said fuel gasifying member having a roughened inner surface for diffusing liquid fuel, which is supplied throught said fuel diffusion member, along said fuel gasifying member, said gas chamber having a central opening communicating with the internal space of said fuel gasifying member with a narrow atomized fuel blowing gap defined therebetween, and an air supply duct extending into the internal space of said fuel gasifying member through said central opening of the gas chamber for directing a stream of air under pressure toward said fuel diffusing member and said fuel gasifying member so as to accelerate the fuel diffusion and fuel gasification and to produce a mixture of the gasified fuel and air.

Other objects, features and advantagesof the present invention will be apparent from the following detailed description taken in conjunction with the accompanying drawings.

FIG. 1 is a longitudinal sectional view of a burner according to the present invention.

FIG. 2 is a side elevation of the burner when viewed from theleft-hand side of FIG. 1.

FIG. 3 is a longitudinal sectional view of a modification of the burner shown in FIG. 1.

FIG. 4 is a side elevation of the modification when viewed from the left-hand side of FIG. 3.

FIG. 5 is a sectional view taken on the line V V in FIG. 3.

FIG. 6 is an enlarged perspective exploded view of the assembly consisting of the rotary shaft and the fuel diffusing member shown in FIG. 1.

FIGS. 7 and 8 are partly cut-away views showing partial modifications of the burner shown in FIG. 1.

Referring to FIGS. 1 and 2 showing an embodiment of the present invention, a substantially frustoconical main body 1 is double-welled along its periphery and at a portion of one of the end openings thereof so as to define a gas chamber 3. The other end opening of the main body 1 provides a flame blowoff nozzle 2. A multiplicity of gasified fuel blowing openings 4 in the forms of slits are formed in the inner peripheral wall of the gas chamber 3 for blowing gasified fuel into a combustion chamber, and the inner wall portions of the gas chamber 3 adjacent to the end remote from the flame blowoff nozzle 2 converge toward the flame blowoff nozzle 2 to define an open space 5 which communicates with the interior of a hollow, substantially frusto-conical fuel gasifying member 7. A rotary shaft 6 extends into the main body 1 and is rotated by means such as a motor (not shown). The fuel gasifying member 7 is mounted on the front end of the rotary shaft 6 and a finely meshed member 8 such as a wire screen 8 is bounded or otherwise fixed to the inner surface of the fuel gasifying member 7. The open end portion 9 of the fuel gasifying member 7 is disposed in slightly spaced relation from the inner end of the open space 5 of the gas chamber 3 so as to define therebetween an atomized fuel blowing gap 10.

A frusto-conical fuel diffusing member 11 is disposed within the fuel gasifying member 7 in coaxial relation with the latter. The fuel diffusing member 11 may be secured to the rotary shaft 6 or to the closed end of the fuel gasifying member 7. A liquid fuel supply conduit 12 extends into the main body 1 to terminate at the front end thereof at a position adjacent to the rear end or smallest diameter portion of the fuel diffusing member 11. The rotary shaft 6 may be hollow tubular as shown by the broken lines in FIG. 1 so as to define a fuel supply passage 12' therein and this passage 12 may communicate with a plurality of radial grooves 17 formed on the end surface of the fuel diffusing member 11 as shown in FIG. 6 so as to supply liquid fuel to the inner surface of the fuel gasifying member 7. In this case, the liquid fuel supply conduit 12 is unnecessary.

An air supply duct 13 extends through the control open space of the gas chamber 3 into the fuel gasifying member 7 in the main body 1 and is connected to a suitable air supplying means such as a blower (not shown) so as to direct a stream of air under pressure toward the fuel diffusing member 11 and fuel gasifying member 7. An ignition means 14 is disposed at a suitable position in an ignition space within the main body 1, and a heat shielding plate 15 is fixed to the rear end of the main body 1 by screws. Further, a plurality of reinforcing ribs 16 are provided in the gas chamber 3.

The gasified fuel blowing openings 4 are not necessarily in the form of the slits shown in FIG. 1. These blowing openings 4 may be formed by the combination of annular pieces as shown in FIG. 7. Further, as shown in FIG. 8, a perforated cylindrical member having many perforations may be detachably mounted in the main body 1.

In the burner having a structure as described with reference to FIGS. 1 and 2, liquid fuel supplied to the burner is centrifugally diffused by the rotation of the fuel diffusing member and is then atomized by the stream of air under pressure supplied from the air supply duct. FIGS. 3 to 5 show a modification of the burner shown in FIGS. l and 2, and in this modification, the above effect can be further improved. Referring to FIGS. 3 to 5, the air supply duct 13 is provided with a plurality of circumferentially spaced air discharge openings l8 for discharging a whirling stream of air under pressure in a direction opposite to the direction of rotation of the fuel gasifying member 7, and a plurality of air stream guide vanes 19 are fixed within the air supply duct 13 at positions corresponding to the positions of the air discharge openings 18, so that the streams of air under pressure discharged from the air supply duct 13 can be directed to the liquid fuel portion atomized in the fuel gasifying member 7 and to the liquid fuel portion gasified already in the fuel gasifying member 7 thereby promoting the atomization and gasification of the fuel more and more and obtaining an ideal gasified fuel air mixture suitable for complete combustion. Provision of the means above described is advantageous in that the atomization and gasification of the liquid fuel portion diffusing along the inner surface of the fuel gasifying member 7 and the liquid fuel portion gasified already in the fuel gasifying member 7 can be further promoted and complete combustion can be ensured.

In operation, when the rotary shaft 6 is rotated in the state shown in FIGS. 1 and 2, the fuel gasifying member 7 and fuel diffusing member 11 are rotated in unitary relation with the rotary shaft 6. Then, when the ignition means 14 is energized and the blower is placed in operation while supplying liquid fuel onto the rotating fuel diffusing member 11 by way of the fuel supply conduit 12, the liquid fuel diffuses along the surface of the fuel diffusing member 11 to be transferred onto the finely meshed member 8 forming the roughened inner surface of the fuel gasifying member 7. While diffusing along such surface of the fuel gasifying member 7, the liquid fuel is completely atomized by the stream of air under pressure discharged from the discharge end of the air supply duct 13, and the atomized liquid fuel portion is forcedly passed through the atomized fuel blowing gap 10 together with a portion of air under pressure and ignited by the ignition means 14 in the ignition space within the main body 1. During the ignition of the atomized liquid fuel portion, a portion of air under pressure passes through the gas chamber 3 and discharged into the combustion chamber from the gasified fuel blowing openings 4 thereby ensuring complete combustion. The combustion gas produced by the combustion flows toward the flame blowoff nozzle 2 thereby heating the fuel gasifying member 7 as well as the main body 1 to a high temperature. Due to this heating action, the atomized liquid fuel diffusing along the fuel diffusing member 1 1 and fuel gasifying member 7 is immediately gasified and is mixed with the stream of air under pressure to provide a readily combustible gasified fuel-air mixture which fills the gas chamber 3. This gasified fuel-air mixture is forced into the combustion chamber through the gasified fuel blowing openings 4 and is ignited immediately by the flame produced by the previous combustion. Further, a portion of gasified fuel is blown through the atomized fuel blowing gap 10 to participate in the combustion. Once the combustion takes place, the rotating fuel gasifying member 7 is heated more and more and the gasification and combustion of liquid fuel sustains over an extended period of time.

It will be understood from the foregoing detailed description that liquid fuel supplied into the internal space of the fuel gasifying member 7'rotated by the rotary shaft 6 within the main body 1 is quickly atomized by the stream of air under pressure supplied from the air supply duct 13 while diffusing along the fuel diffusing member 11 and along the roughnened inner surface 8 of the fuel gasifying member 7, and the atomized fuel is blown into the ignition space of the main body 1 through the atomized fuel blowing gap 10 for heating the main body 1 and fuel gasifying member 7. Further, due to the fact that the main body 1 and fuel gasifying member 7 can be quickly heated, the fuel diffusing along the fuel gasifying member 7 can be quickly gasified to be thoroughly mixed with air under pressure in the internal space of the rotating fuel gasifying member 7, and the gasified fuel-air mixture is blown into the combustion space through the gasified fuel blowing openings 4 to attain continuous combustion. According to the present invention, therefore, the state of combustion of fuel in liquid form can be immediately shifted to the state of combustion in gasified form without provision of any especial switch-over means. Thus, the prior art defects including the long period of time required for preheating and troublesome removal and replacement of the injection plate can be eliminated. further, according to the arrangement shown in FIGS. 3 to 5, the means 18 and 19 act to discharge a stream of air under pressure in a direction opposite to the direction of rotation of the fuel gasifying member 7. This arrangement is effective in further promoting the atom ization of diffused liquid fuel and thoroughly mixing the gasified fuel with air. Thus, liquid fuel having a high viscosity can even by automatically gasified for complete combustion.

l claim:

1. A burner for burning liquid fuel in gasified form,

comprising a main body formed by a part having a gas chamber on the periphery thereof,

a combustion chamber within said main body,

a plurality of gasified fuel blowing openings formed on the inner periphery of said gas chamber for blowing gasified fuel into said combustion chamber,

a rotary shaft extending coaxially into said main body and carrying a hollow fuel gasifying member at one end thereof, said fuel gasifying member having a fuel diffusing member provided on the inner surface thereof, said rotary shaft extending through said fuel diffusing member for rotation,

said fuel gasifying member having a roughened inner surface for diffusing liquid fuel, which issupplied throught said fuel diffusion member, along said fuel gasifying member,

said gas chamber having a central opening communicating with the internal space of said fuel gasifying member with a narrow atomized fuel blowing gap defined therebetween, and

an air supply duct extending into the internal space of said fuel gasifying member through said central opening of the gas chamber for directing a stream of air under pressure toward said fuel diffusing member and said fuel gasifying member so as to accelerate the fuel diffusion and fuel gasification and to produce a mixture of the gasified fuel and air.

2. A burner as claimed in claim 1, further comprising a plurality of air discharge openings formed on the wall of said air supply duct in a suitably circumferentially spaced relation, and a plurality of stationary guide vanes disposed in said air supply duct at positions corresponding to the positions of said air discharge openings for directing a whirling stream of air under pressure toward the inner surface of said fuel gasifying member in a direction opposite to the direction of rotation of said fuel gasifying member and for further accelerating the fuel diffusion by blowing the air discharged from said air discharge openings against the fuel diffused along the inner surface of the fuel gasifying member.

3. A burner as claimed in claim 1, wherein said roughened surface of said fuel gasifying member is formed by a wire screen.

4. A burner as claimed in claim 1, wherein a plurality of grooves are formed on the front end surface of said fuel diffusing member, and said rotary shaft is in a hollow tubular form for supplying liquid fuel to said grooves of the fuel diffusing member. 

1. A burner for burning liquid fuel in gasified form, comprising a main body formed by a part having a gas chamber on the periphery thereof, a combustion chamber within said main body, a plurality of gasified fuel blowing openings formed on the inner periphery of said gas chamber for blowing gasified fuel into said combustion chamber, a rotary shaft extending coaxially into said main body and carrying a hollow fuel gasifying member at one end thereof, said fuel gasifying member having a fuel diffusing member provided on the inner surface thereof, said rotary shaft extending through said fuel diffusing Member for rotation, said fuel gasifying member having a roughened inner surface for diffusing liquid fuel, which is supplied throught said fuel diffusion member, along said fuel gasifying member, said gas chamber having a central opening communicating with the internal space of said fuel gasifying member with a narrow atomized fuel blowing gap defined therebetween, and an air supply duct extending into the internal space of said fuel gasifying member through said central opening of the gas chamber for directing a stream of air under pressure toward said fuel diffusing member and said fuel gasifying member so as to accelerate the fuel diffusion and fuel gasification and to produce a mixture of the gasified fuel and air.
 2. A burner as claimed in claim 1, further comprising a plurality of air discharge openings formed on the wall of said air supply duct in a suitably circumferentially spaced relation, and a plurality of stationary guide vanes disposed in said air supply duct at positions corresponding to the positions of said air discharge openings for directing a whirling stream of air under pressure toward the inner surface of said fuel gasifying member in a direction opposite to the direction of rotation of said fuel gasifying member and for further accelerating the fuel diffusion by blowing the air discharged from said air discharge openings against the fuel diffused along the inner surface of the fuel gasifying member.
 3. A burner as claimed in claim 1, wherein said roughened surface of said fuel gasifying member is formed by a wire screen.
 4. A burner as claimed in claim 1, wherein a plurality of grooves are formed on the front end surface of said fuel diffusing member, and said rotary shaft is in a hollow tubular form for supplying liquid fuel to said grooves of the fuel diffusing member. 